Planograpii



H. H. WAIT.

STEAM TURBINE.

APPLICATION FILED AUG-26, I916.

Patented Sept. 9, 1919.

' 4 SHEETS-SHEET 1.

H. H. WAIT. STEAM TURBINE.

APPLICATION FILED AUG.26. 1916.

Patented Sept. 9, 1919. 4 SHEETS-SHEET Z mm W. m1 W o D 9. 0 MW u mmMM Al w ww MN MW Patented Sept. 9, 1919.

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H. H. WAIT.

STEAM TURBINE;

- APPLICATION F-ILED AUG-2G. 1916. 1,31 5,263. Patented Sept. 9, 1919.

4 SHEETS-SHEET 4- HENRY H WAIT, OF CHICAGO, ILLINOIS.

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the buckets at the other .side of the wheel; by reversing guides by which the steam is again directed to the buckets of the wheel whence it goes to exhaust. The invention is more particularly concerned with said return guides and the nozzles by which steam is admitted to the turbine and the arrangement of these parts relative to the casing and other parts of the turbine. A prime object of the invention is to provide a guide which shall be easy and inexpensive to manufacture and to apply to the turbine without sacrificing any of the advan tages which are found in connection with more expensive constructions. Other ob jects and advantages of the invention will appear from the accompanying drawings and the following description in which I have set forth a preferred form of the invention. It is to be understood, however, that the specific disclosure is for the purpose of exemplification only, and that the scope of the invention is defined in the following claims, in which I have endeavored to distinguish it from the prior art with; out, however, relinquishing or abandoning any portion or feature thereof.

In. the accompanying drawings Figure 1 is a side elevation of a preferred form of my invention, the steam inlet, however, being shown in section; Fig. 2 is a fragmentary section on the lineQ-Q, of Fig. 3 parallel tothe plane of Fig, 1; Fig. 3 is a vertical axial section on the line 3.-3 of Fig. 1, parts being shown in elevation; Fig. is a development in section onthe line H of Fig. 1; Figs. 5,.6 and 7 areperspective, end and edge views,respectively, of one of the steamreturn guides removed from the casing; Figs. 8 and .9.are. elevations ofdetails of the guides; and. Fig. 10 is an enlarged. transverse section througha portion of a nozzle, wheel and guide. Each part is Specification of Letters Patent.

identified by the same reference character wherever it appears inthe several views;

The casing of the turbine is or may be composed of nijain casting 9 in which the wheel chamber is formed, and which comprises a braclret 10 for sup oortingthe bearing-castin'g 11, in which one end of the wheel shaft is journaled. The casting 12 forms a face plate fittingu'pon andbolted to the main castingand closing the wheel chamber. It also comprises a "bracket 13 towhich the bearing-casting lfor the other endof the turbine wheeljsliaft 15 is securedl The face plate is formed with openings "16, 16, surrounded by external bosses 17 which receivethe nipples 18 which carry the nozzjles 1-9, 19, (see Fig. 4), Nipples 18 are formed with external flanges 20 which are perforated and secured between theunions 21 and 22, and the bosses 17, bybolts23 extending through the flanges "on said unions, the flanges on the nipples and into the face plate. In the construction selected for exemplification a main and an auxiliary nozzle are employed, the main nozzle being indicated by thecharacterltl, and the auxiliary nozzle by the character 19', butit will be obvious that the auxiliary nozzle is not essential, but may be used to increase the power of the turbine. Where the mainand auxiliary nozzles are employed, however, they are connected together as by a pipe 24,

'connected by flanges 25, 26, to similar flanges upoirthe unions.

Thenozzles are screwed into theends of the nipples, projecting at the acute angle to the sideor face of the turbine wheel, and are slightly flared and cut away upon one side on a plane parallel to the face of the turbine wheel so that they fit closelyto the edges of the series of buckets, but have a slight'clearance therefrom. For the purpose "of the present invention the precise construction of the wheel and buckets is not material provided the latter are of the well known curved type. The wheel shown for the purposeof illustration. is a disk 27 of metal plate, perforatedat 28 to receive the axle and provided upon opposite sidesthereof with perforated disks 29riveted thereto and forming hubs therefor to brace the wheel with relation to the axle. The plate disk is cut away upon one side atSO to form an annular groove of the cross-section V Patented fiept. 9,1919. Application fi1ed August 26, 191s. "Seria1No.11'7,b S6.

the buckets 33, which are secured thereto by rivets or'bolts 34. By chamfering the flange of the wheel, the corresponding face of thelatter is brought flush with the buckets notwithstanding that the latter are short and at the same time symmetrical with respect to the rivets, by which they are securedto' the wheel. A band 35, which may be integral or. in sections, but preferably the former, surrounds the buckets and is also held by therivets which are upset or headed over outside the band. The main casting 9 and the face plate 12 are each formed With stufling boxes 36, 37, .within which see tionalpacking rings 38, 39 are maintained in engagement with the shaft by means of spiral spring rings or garters 40; cover plates 41, 41 are bolted to the main casting and face plate respectively for closing the stufiing boxes. The main casting and face plate are each formed with a series of radial strengthening ribs 42, 43, and the main cast ing 9 is formed with a pocket or pockets 44 projecting outwardly between said ribs ,andjwhich receive the steam return guides to be presently described.

The guides consist each of a supporting member 45, a cover plate 46, and an inter- (See Figs. 5 to 8 inclusive.)

mediate series of guide ribs or blocks 47. The support 45 comprises a rib 48 and a curved plate 49, the rib being formed with bolt holes 50, 51, by which the support is bolted to bosses 52 formed upon the casing. (See Fig. 3). The

curved plate 49, when the support is bolted in place, is concentric with the wheel. The guide blocks orribs, the outlines of which are best shown in Figs. 4 and 8, are cast in brass and preferably in a single casting.

(See Fig.

connected by bridgesor webs .5'3. 8) These blocks comprise an outer marginal wall 54, an inner block 55 tapered throughout except at the larger end where it isrounded as at 56, and one or more crescent; shaped blocks 57, 58 which are so shaped and arranged as to provide two or s more curvedrchannels 59, 60, 61, to receive the steam from the bucketsof the wheel after it has been deliveredrthereto by the edges of the blocks 63, 64 are filed to sharp chisel edges.

The combined cross-sectional area of the channel or channels of the guide passages is approximately uniform throughout as will be understood by those familiar with this art. This cross-sectional area is dependent to a certain extent upon the peripheral speed of the wheel, so that with a given circumferential span of the nozzle on the wheel blades it is desirable to be able to vary this crosssectional area without restricting the circumferential span of the entrance to the guide passage so that the steam emerging from the wheel blades would impinge on 'dead walls as at 54, 55 in Fig. 4. To this end it is sometimes advisable to make the radial depth of the main part of the guide passage, as at in Fig. 10, less than the radial height of the wheel blades, 211d the entrance to this passage can then be flared as shown in Fig. 10, so that the steam jet emerging from the wheel will not impinge against the inner and outer circumferences of the passage. With a' View to avoiding the impinging of the steam jet on the edges of the wheel and wheel band at the discharge end of the guide passages, I slightly file away, or chamfer the intermediate mem bers as at 65, (see Figs. 4 and 8) so as to make the face thereof adjacent the wheel of slightly less width at this portion, and when the cover is applied thereto it is bent or swaged down at 65 (Figs. 7 and 9) to fit snugly against the chamfered edge, bywhich means the channel at its outlet is slightly reduced in diameter as compared with the original diameter and with the radial dimension of the buckets. At the receiving end the channels are widened by filing, cutting away, or chamfering the cover plate and support at 66, 67, (see Figs. 9 and 10) in register with the channels of the intermediate member, so that the inlet ends of these channels are slightly flared and thus widened beyond the radial dimension of the buckets. After the several elements of the guide have been treated in the manner just described, they are assembled and riveted together by the rivets 69, when the guide is ready for application to the turbine casing. Thus the entire making and assembling of the guide is accomplished outside the turbine casing and the riveting of the parts together may be accomplished at a single operation. The return guide is then bolted to the ribs of the casing as heretofore described.

It is sometimes desirable to be able tn mount the turbine for right or left-hand rotation. For this purpose no change in the casing is required, but the wheel or the buckets thereon must be reversed and the nozzles turned through an angle of 180 degrees to the position shown in dotted lines 1 eases in Fig. 4. The steam guides must be reversed in direction as shown in dotted lines in said figure. In order to avoid duplication of bolt holes forsecuring theguides in the opposite positions when the casing is constructed to permit of reversal ofro-tation, 1 form one of the bolt holes in the casing directly opposite the aperture for thenozzle with which the guide to be securedjby said bolt hole cooperates, and the rib 48 is extended at the receiving end of the guide be. yond the latter, and the hole 50 formed therein through which that end of the guide may be secured to the'casing by a bolt passing through said .holes inthe guide and easing respectively. (See Fig. 5).

I claim:

1. A return guide for a steam turbine of the axial flow reentrant type, comprising a cylindrically curved supporting member, cylindrically curved channel strips arranged upon the cylindrical surface of said mem her and so spaced from each other as to form axially reentrant steam passages and a separate cover plate fitting over said strips.

2. A steam return guide for a steam turbine of the axial flow reentrant type comprising a cylindrically curved supporting member having an external longitudinal stiffening and supporting rib thereon, and adapted for attachment to the side wall of a turbine, channel strips secured upon the cylindrically curved face of the supporting member and so spaced as to form suitable steam channels, and a cover plate fitting over said strips.

3. A steam return guide for a steam turbine of the axial flow reentrant type comprising a support consisting of a tapering cylindrically curved plate, and a rib normal thereto and adapted to be secured to the side wall of the casing of a turbine, a plurality of cylindrically and axially curved channel strips secured to the cylindrlcal face of the support, and so spaced as to form therewith suitable steam passages, and a cover plate arranged over sald strips.

4. A steam return guide for a steam turbine of the axial flow reentrant type co1nprising a support consisting of a cyl1ndr1- cally curved plate, tapering toward one end,

a rib arranged longitudinally of said support and adapted to be secured to a casing of a turbine, channel strips upon the cylindrical face of the support, and a cover plate arranged over said channel strips.

5. In a steam turbine of the axial flow reentrant type, a casing comprising oppos te relatively parallel walls and a web connecting said walls, a shaft extending through said walls, a turbine wheel mounted on said shaft, a nozzle mounted on one of said walls and adapted to supply the turbine Wheel with steam, a pocket formed in the other of said walls, and a steam return guide operating wlth said wheel extendmg into saidpocket and afiange on said guide by.

which the same is secured to the face ofthe wall in which said pocket is formed.

6. In asteam turbine, acasing compris 111g a pa1r of substantially parallel walls, a

web connecting said walls, a nozzle secured in lone of said walls, a shaft extending through said walls, the turbine wheel mounted on the shaft, the other of said walls beingformed with a recess, a separate steam return guide structure extending into said recess, and comprisinga support having a rlb thereon, and axlal bolts securing said rib to the face of the last said wall.

and channel strips curved circumferentially and axially arranged between said support and plate, said channel strips being of substantially constant height in the main part of the passage but chamfered near the out let end of the channels therein, and said cover plate being bent to fit against the chamfered portion of said strips.

9. A steam return guide having a steam turbine of the axial flow reentrant type comprising a support having a cylindrical surface, strips supported on said cylindrical surface and spaced apart from each other to form return channels for the steam, said channels being curved circumferentially and axially, and a cover plate secured to said stripsand support, and having its edges adjacent the passages between said strips chamfered to produce a flare in the mouths of the channels.

10. In a steam turbine, a steam return guide comprising a support, consisting of a cylindrical guide portion and a radial rib portion extending at one end beyond the body of the guide and formed for attachment to the casing-of the turbine.

11. A guide for a steam turbine of the axial flow type adapted to receive a jet of steam discharged from the blades of the wheel and direct said steam jet to a second impact with the same wheel, said guide being cylindrically curved having a steam passage therein flared at the receiving end, the intermediate portion of the steam passage being of substantially'uniform cross section.

12. A guide for a steam turbine of the axial flow type adapted to receive a jet of steam discharged from the blades of the impact With the same wheel, said guide having a steam passage therein flared at the reeeiving end and constricted at the discharge end, the intermediate portion being of substantially uniform diameter. v

13. A steam turbine comprising a Wheel With radial blades and a casing, said Wheel being ehamfered at the rim, a return guide adapted to receive a jet of steam discharged from the blades of the Wheel and consisting of a cylindrical supporting member having guide strips secured thereto, said supporting member being ehamfered to correspond with the chamfer of said Wheel.

14; A steam turbine comprising a casing and a Wheel, the latter having buckets thereon, a return guide having a passage therein of approximately constant cross section adapted to receive steam discharged from the blades of the Wheel, the main part of said passage being of less height than the wheel blades and the receiving end of said passage being flared to a greater radial height than said Wheel blades.

HENRY I-I. WAIT.

Copies of this patent-may be obtained for five cents each, by addressing the Commissioner of Patents,

. i Washington, D. G. 

